Wet granulation method for generating granules

ABSTRACT

A method of wet granulation of fertilizer and other materials into granules. The method involves formation of the granule directly on the pan from the feedstock without intermediate steps or the use of seed materials. The result is a product having a completely uniform cross section. The feedstock is initially in the size distribution of −150 mesh with 90% or greater in the size range of 200 mesh. Moisture is maintained to facilitate a steady process without cycling.

FIELD OF THE INVENTION

The present invention relates to a pan granulation method for pangranulating pellets or granules and more particularly, the presentinvention relates to a wet granulation method for granulating fertilizerand other materials into industrially useful pellets or granules.

BACKGROUND OF THE INVENTION

One of the greatest limitations existing in the granulation art iscentered on the fact that known processes require a seeding agent inorder to achieve the proper conditions for material accretion to resultin a pellet or granule. By making use of a seed, the resulting granuleis adversely affected in two key properties; roundness and crosssectional uniformity. Typically, seeding material is not round and asthe precursor particle, the result is irregular initial feedstockaccretion which, in turn, forms an out-of-round particle upon whichfurther material accretes. A further detriment from this results interms of nonuniform particle density.

Methodology is required for synthesizing a granule in the absence ofseed material and which is round, tightly packed with a uniformhomogeneous cross section and capable of eliminating hazards associatedwith fertilizer granule production.

One of the latest issued patents in the art to which the presentinvention relates is U.S. Pat. No. 5,460,765, issued to Derdall et al.,Oct. 24, 1995. The reference teaches a process for pan granulating aparticulate material. Based on the teachings of the Derdall et al.reference, a final particle size distribution that is achievable bypracticing the invention is between about −5 mesh to about +10 mesh. Inorder to initiate the process, the Derdall et al. process is limited tothe introduction of a seeding material typically between about −14 meshand +28 mesh. This is required in order to control the granule growthand as indicated in the Derdall et al. disclosure, seed minimizes mutualagglomeration and results in high yields being obtained. The Derdall etal. reference further indicates that the proper sizing of the seed isfundamental to the operation of the process for granulation in order tohave product yields exceed 90%. Reference is made in the disclosure thata seed core in the range of −14 mesh to +35 mesh is required in order toachieve a steady state and maintain uniform size distribution of between−8 mesh to +6 mesh.

The Derdall et al. process, although a meritorious procedure, did notrecognize the limitations of employing a seeding agent or the need forcontrolling the dust generated during granulation which not only createsan unhealthy environment for workers, but more seriously, results in apotentially explosive environment. This is evident from the teachings ofDerdall et al., particularly at column 3, beginning at line 24, whereinit is stated:

“It may be more difficult to keep the granulation steady or stable withfine seed, such as −35 mesh.”

The difficulty to which the Derdall et al. disclosure alludes isdirected to cycling which is an inherent problem with pan granulationprocesses. If the size distribution of the seeding agent is notconstant, then the process will not stabilize and effectively “cycles”as is known to those skilled in this art. The result of this is thatlarger formed granules on the pan effectively destroy the smallerparticles. This, of course, defeats the purpose of the pan granulationto generate particles.

Furthermore, at line 36 in column 3, the disclosure indicates that:

“Fine seed sizes can be used, such as +35 mesh, but a point is reachedwhere over-seeding or nucleation occurs easily and causes the finalproduct yield to drop down.”

It is also indicated at column 3, beginning at line 45 that:

“Seed material in the range of 20 mesh is the best single point for eachof control and uniformity of product size distribution . . . ”.

As is known, the larger the mesh numerical value the smaller the micronsize of the particle. The following mesh sizes correspond to the statedmicron sizes:

Approximate Mesh Size Micron Size 12 1680 16 1190 20 840 30 590 40 420100 149 200 74

Based on the teachings of the Derdall et al. disclosure, mesh sizesgreater than +35 caused potential nucleation problems and result in afinal product yield to decrease. With the technology disclosed, infra,it has been found that by using a fine powder of between −35 mesh to+150 mesh, that the superior quality product can be formed in high yieldand typically in the range of a greater than 90% yield. When the abovepassage regarding Derdall et al. is considered, it is clear that Derdallet al. effectively contradict what the technology set forth herein hasfound to be particularly successful.

In the present application the size distribution of the nucleatingmaterial is between −35 mesh and +150 mesh which corresponds to micronsize less than 590 μm and 105 μm, respectively. Nowhere in the priorapart is a powdered nucleating agent in this size distribution disclosedfor the purpose of forming a uniform granule in the size distribution of−8 mesh to +4 mesh. Advantages have been ascribed to this process andone of the most attractive advantages is that the granule or pellet hasan enormous break strength and a uniform cross section. It has beenfound by practicing the present invention, that break strengths in therange of 1 to 4 kgs or greater have been achieved.

In the Derdall et al. disclosure, at column 3, beginning at line 33 itis stated:

“Seed of large size forms granules of very poor strength.”

If one considers these teachings in light of the size of the nucleatingagent provided herein, the admissions made in the Derdall et al.disclosure would clearly go against the appeal of using a seeding agentin the size range as clearly taught by Derdall et al. The; instructionin Derdall et al. indicates an ideal seeding agent size is 20 mesh(supra); the instant application uses a powder having a particle sizebetween 75-750% smaller than Derdall et al. and yet achieve verydesirable results.

In Statutory Invention Registration H1070, authored by Harrison et al.,Jul. 7, 1992, a method for granulating potash materials is disclosed.The process involves the conversion of particulate potassium sulfate orpotassium chloride by agglomeration using a conventional rotary drumgranulator, pan granulator or other conventional granulating device.

In the disclosure of this document, there are no specific teachingsregarding the elimination of a seeding agent, feedstock size or otherimportant factors related to process control in order to generatesuperior quality granules having commercial viability. Further, theprocess clearly is an agglomeration process. It is known thatagglomeration typically involves the aggregation of colloidal particlessuspended in a liquid into clusters or flocs. These clusters or flocshave varying degrees of interstices and are loosely bound (Hawley'sCondensed Chemical Dictionary, eleventh edition, 1987).

As a particularly advantageous feature of the present invention, themethodology herein facilitates sulfur granulation. With theeffectiveness of air pollution regulations, it has now become necessaryto augment the soil with sulfur due to deficiencies. As is generallyknown in agricultural science, sulfur fertilization increases crop yieldand quality and further has an effect on nitrogen processing by plantmatter. This processing is, in turn, related to protein synthesis,nitrogen fixation, photosynthesis and disease resistance.

Currently, sulfur pelletizing or granulation processes proceed accordingto dry synthesis methodology. This is extremely hazardous since sulfur,particularly sulfur dust, is explosive and difficult to handle. In viewof these serious limitations, the field is in need of a viable and safegranulation process. The present technology set forth herein delineatesa nonhazardous method for granulating sulfur, customizing particle sizeas well as additive addition to produce sulfur particles capable of slowrelease, pesticidal, herbicidal and bactericidal activity inter alia.

Wet granulation is inherently complicated, since irregular particlecrystallography is inherently difficult to control. Wet powder is notuniform and this leads to non-uniform accretion, over nucleation andeventual breakdown of the process. For these reasons among others, theart has not realized an effective and viable process for wetgranulation.

Boeglin et al. in U.S. Pat. No. 3,853,490, discloses a granulationmethod for granulating potassium sulfate. The method involves the use oflarge particle starting material −6 +65 mesh (50%), −200 mesh (10% to30%) and the remainder comprising −65 +200 mesh. In the disclosure it isstated that the granulation is carried out in conventional granulatingequipment, however, there is no discussion concerning process controldifficulties associated with pan granulation of the product. It is knownfrom Derdall et al. that significant difficulties are encountered inkeeping the granulation steady even with seed material in the size rangeof +35 mesh. The most difficult problem is controlling “cycling” wherethe larger particles destroy the smaller particles. The Boeglin et al.reference would therefore appear to be directed solely to a drumgranulation process where the complications inherent with pangranulation are not encountered.

In U.S. Pat. No. 3,711,254, issued to McGowan et al., there is discusseda process for granulating potash. The disclosure of the document onlyprovides a cursory teaching of granulation and includes pan and drumgranulation within the same process.

Kurtz, in U.S. Pat. No. 5,322,532, discloses a sodium bicarbonate blastmedia. The blast media comprises an agglomeration of sodium bicarbonateand sodium sesquicarbonate. The reference does not set forth any detailswith respect to any other formulation process apart from agglomerationand lacks instruction regarding any other material for augmentation.

Other patent documents of only marginal relevance include the followingU.S. Pat. Nos.: 4,371,481; 4,131,668; 4,264,543; 5,108,481; 3,206,508;3,206,528; 4,344,747; and, 5,124,104,

The prior art, when taken singly or collectively, is deficient any clearteachings regarding the preparation of fertilizer, blasting, deodorizeror water softener granules having the following commercial andindustrial advantages:

a) uniform cross section;

b) tightly packed feedstock;

c) absence of a seed or crystal core;

d) increased break strength relative to the prior art;

e) material homogeneity throughout the granule; and

f) greater quantity of feedstock material per granule

There has been a long felt need for granules having these desirableproperties and for methodology to effect synthesis of such products; thepresent invention addresses these needs in an elegant and efficaciousmanner.

SUMMARY OF THE INVENTION

One object of the present invention is to provide an improved method forgenerating a variety of industrially useful particles or granules, whichparticles are devoid the drawbacks of the prior art techniques.

A further object of one embodiment of the present invention is toprovide a wet granulation method for granulating a feedstock intogranules, comprising the steps of:

providing a feedstock having about 99.9% particle size of −150 mesh of99.9% particle size of −150 mesh about 90% comprising a particle size of−200 mesh;

providing a binder material in an amount of about 6% to about 8% byweight;

contacting the feedstock with the binder on a pan granulator undermoisture conditions where the moisture content on the pan is betweenabout 1.5% to about 11% by weight; and

forming granules on the pan directly from the feedstock in the absenceof seed or nucleating material.

In the present invention, the maintenance of moisture on the pan and inthe product substantially prevents dust formation during productsynthesis. This is augmented by the addition of oil e.g. mineral,vegetable, seed, synthetic, etc. to the final product. As a furtherfeature, plant nutrients, growth regulators, minerals, time releasecompositions and suitable bacteria may be included in the granules. Interms of the nutrients, suitable examples include nitrogen, phosphorousand potassium; the growth regulators may be herbicides, pesticides,hormones; the minerals will vary depending on soil and environmentconditions, but may include copper, boron and other metals; the timerelease materials may be selected to release the sulfur only at specifictimes during the growth cycle of the plant, crop, etc.; bacteria may beselected from a diverse variety depending on the specific requirementsof the user. To this end, sulfur oxidizing bacteria may be selected,disease combating bacteria to reduce the vulnerability of the crop etc.

As another feature of the present invention,, the technology can beeasily employed in the granulation of pellets/granules used in otherfields outside of the agricultural sciences. One such field is theblasting art. In this field, it is well known that sodium bicarbonate isa useful blasting medium in view of the copious benefits associatedtherewith. The bicarbonate is useful, but the crystals are such thathigh efficiency in coating removal from a substrate is not entirelypractical. The present technology facilitates granulation of thebicarbonate with further crystalline materials to augment theabrasiveness of the granule.

The important inventive concept of the present invention is the abilityto generate particles/granules in the absence of a seeding agent. Inthis manner, the process can be loosely referred to as a pan nucleationprocess; the process proceeds generally as crystallization, i.e., anucleation site accretes the surrounding material. With the presenttechnology, the pan rotation and binder assist in the material accretionaround the nucleation site to produce a tightly packed granule with highfeedstock content.

Having thus described the invention, reference will now be made to theaccompanying drawing illustrating preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic representation of the method according toone embodiment of the present invention;

FIG. 2 is a photograph of a sulfur granule in cross section formulatedby practicing the prior art methodology;

FIG. 3 is a photograph of the sulfur granule of FIG. 2;

FIG. 4 is a photograph of sulfur granules in cross section formulated bypracticing the methodology of one embodiment the present invention;

FIG. 5 is a photograph of the sulfur granules of FIG. 4;

FIG. 6 is a photograph of a potassium chloride granules formulated bypracticing the methodology of the prior art;

FIG. 7 is a photograph of red potassium chloride granules in crosssection formulated by practicing the prior art methodology;

FIG. 8 is a photograph of potassium chloride granules in cross sectionformulated by practicing the methodology of one embodiment of thepresent invention;

FIG. 9 is a photograph of a potassium chloride granule illustrated inFIG. 8; and

FIG. 10 is a photograph of potassium chloride granules containing sulfurand formulated by practicing the methodology of one embodiment of thepresent invention;

Similar numerals employed in the text denote similar elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Prior to the explanation of the method, the following table sets forthsome general properties of the compounds and materials that may begranulated.

TABLE 1 GENERAL PROPERTIES MELTING BOILING COMPOUND CRYSTALS SOLUBILITYPOINT (C.) POINT (C.) HAZARDS Ammonium colorless soluble in water, 169.6Decomposes may Nitrate- alcohol and at 210 explode if NH4NO3 alkaliesconfined and exposed to high temperature Ammonium brownish white solublein water 513 none Sulfate- to gray (NH4)2SO4 Potassium colorless orsoluble in water; 772 sublimes at none Chloride-KCl white slightly in1500 alcohol Potassium transparent, soluble in water 337 decomposesfire/ Nitrate KNO3 colorless or or glycerol; at 400 explosion white;powder slightly soluble risk upon or crystalline in alcohol shock orheating or when in contact with organic materials Potassium colorless orsoluble in water 1072 none Sulfate K2SO4 white hard crystals or powderSulfur-S alpha form slightly soluble alpha combustible rhombic, inalcohol and approx in finely octahedral ether, soluble in 94.5 dividedform yellow crystals; carbon disulfide; Beta a fire and beta form carbonapprox explosion monoclinic, tetrachloride and 119 risk exists prismaticpale benzene yellow crystals Urea white crystals soluble in water 132.7Decomposes none CO(NH2)2 or powder alcohol and benzene Sodium whitepowder soluble in water loses none Bicarbonate or crystalline carbonNaHCO3 lumps dioxide at 270

Referring now to FIG. 1, shown is an overall schematic representation ofthe process according to one embodiment.

In the embodiment shown, the circuit is representative of a ten ton perhour circuit. Reference numeral 10 denotes the introduction of feedstockwhich may be any suitable material, numerous examples of which have beenindicated supra. The technology set forth herein permits the formationof most any granulated product including various sulfates, soda ash,sulfur, potash, kaolin, magnesia, potassium sodium and ammonium chlorideinter alia.

The feed may be introduced at 9.8 tons per hour (9.8 thr−1) along withsuitable binder material as set forth herein previously. The feedstockand binder maybe then introduced into a pulverizer 12 to pulverize thefeedstock such that a product is produced having 99.9% −150 mesh and atleast 90% −200 mesh. The pulverizer 12 may be a classifying pulverizeror air sweep pulverizer or any other suitable pulverizer known by thoseskilled in the art. Once pulverized, the stream, generally representedby numeral 14, is introduced into a sealed collection hopper, globallydenoted by numeral 16, which includes a bag house 18 to collect dust.Collection hopper 16 includes suitable valve 20 for metering dust into acollection bin 22. The bin 22 is mounted over two feeders 24 and 26which divide the material being received from bin 22 into two streams,the first stream being fed by feeder 26 to a wet mixer (not shown) andthen to a first large pan granulator 28 at a rate of 7.6 tons per hour(7.6 thr⁻¹), as an example, while feeder 24 feeds a second stream into apaddle or pin mixer (not shown) and then to a second pan granulator 30,being smaller than granulator 28. The feed rate to the small pan may be2.8 tons per hour (2.8 thr⁻¹), as an example, to, be consistent with aten ton per hour circuit. The mixers each contain a mixture of binderand feedstock with a moisture content in the range of 4% to about 8% byweight. The material fed from the mixers to the pans is thus wet andthis avoids dust formation during processing. The amount of moisture inthe binder is a variable factor and is dependent upon the nature of thebinder (solid/moisture content). Clearly, high moisture content binderswill not require as great an addition (on a percentage by weight basis)to the mixers as the lower moisture content binders.

Pan 30 is equipped with a small receptacle 32 for retaining −35 mesh dryraw feedstock (not shown). The receptacle 32 is equipped with a variablerate metering apparatus (not shown). The feeder removes the materialform the receptacle 32 and introduces the dry raw feedstock into pan 30.As is known in the art, the pan granulators 28 and 30 include upper andlower scrapers 34, 36 and 38, 40, respectively. Regarding the feedstockfrom receptacle 32, the same is introduced to the pan 30 behind topscraper 38. In this example, the production rate for the pan 30 would beset for 3 tons per hour (3 thr⁻¹) with a size distribution ofapproximately 80% product between −8 mesh to +20 mesh. It has been foundthat this is achievable by combining the raw feedstock to the dust at aratio of 1:20 to 1:100 parts. The use of an atomizing hot bindersolution at any position from the 12 o'clock through to the 5 o'clockposition has been found to be particularly useful. When the correct freemoisture is attained, generally between 1.5% to about 11%, the first panstabilizes at a steady state condition. In this manner, granules areformed directly on pan 30 in the absence of a seeding agent.

As indicated above, the product formed from pan 30 is typically between50 to 80% −8 mesh. The product is discharged and dried with dryer 39.Dryer 39 be selected from, for example, Carrier dryers, tray dryers orroto louver type dryers. The product being formed in large pan 28 isadditionally transported to dryer 39 via a suitable conveyer, globallydenoted by numeral 41.

Product exiting dryer 38 via stream 42 is then screened by a suitablescreening arrangement 44 at 4 mesh, 8 mesh and 20 mesh. The +4 and −20mesh portions are sent to pulverizer 12 for recycling into the system,the recycling stream being indicated by numeral 46. The −4 to +8 meshportion is the final product and leaves screen 44, as indicated bynumeral 48, as a final finished product. The −8 to +20 mesh portion issent via stream 50 to a hopper equipped with a weigh belt feeder,broadly denoted by numeral 52. The material is advanced from the weighbelt feeder 52 into pan 28 whereupon the product is further processed bythe introduction of binder and additional dust to produce a desiredgranule product. This is an optional step dependent upon whether furtherfeedstock accretion is desired.

Any residual dust which may be present in dryer 39 may be passed vialine 54 for exiting dryer 39 to hopper 56 and the collected material inhopper 56 either passed onto the bag house 18 via line 58 or passed intothe feedstock via line 60. The fines or dust entering bag house 18 mayadditionally be passed off onto ancillary operations, for example, wetscrubbing, as broadly denoted by numeral 60 in FIG. 1. Other exampleswill be readily apparent to those skilled in the art.

The ratio of −8 to +20 mesh product needed to run pan 28 at a steadystate has been found to be, for the system described herein, between1:10 to 2:5, an optimum of 1:5. Pan 28 stabilizes quickly and producesyields of greater than 95% on +8 to −4 mesh. The process yield from theoverall circuit as set forth herein exceeds 90%. As discussed brieflyherein previously, 10% of the weight, which is in the −20 and +4 meshsize distribution, as well as dryer dusts, can be recycled to enhancethe efficiency and productivity of the method to produce maximum yieldsat very low cost.

With further reference to the pans 28 and 30, as is known, the pans maybe adjusted for angle and rotational speed such that the +8 to −4 meshgranules are only produced. In addition, it has been found advantageousto not only change the horizontal disposition of the pans, but also tolaterally tilt the pans to enhance the efficiency of the granulatingprocess. The specific angle of tilt and horizontal angle will bedependent upon the rotational speed and the size of the granule desiredto be produced. As a variation, the tilt and/or angular velocity of thepan(s) may be adjusted to produce granules in the size distribution of−10 mesh to about 100 mesh.

It will be appreciated that the method for operation as discussed can bea single operation or may be incorporated into a unit operation within aseries of other operations. This will depend upon the specific needs ofthe user.

It will also be readily appreciated that any number of pans can beincorporated into the system to progressively grow or accrete a granule.To this end, the process is interruptible and therefore can be customdesigned to produce granules having a variety of layers of material toproduce a host of valuable granules. It will be clear to those skilledin the art that the process is effective for producing a number ofdifferent forms of fertilizer and has particular utility with respect tothe formation of high grade fertilizer for use on golf courses, timerelease formulae etc.

In terms of the binder, suitable examples include lignosol, sugars,saturated salts and proteins, water, calcium sulfate, sodium sulfate,potassium chloride, dry gluttens, wheat grains, barley grains, ricegrains and calcium phosphate among others. The choice of the binder willdepend on the desired characteristics of the granule and accordingly,the aforementioned examples are only exemplary. In the instance wherethe material to be granulated is dangerous or has the characteristic ofhaving explosive dust, the binder composition may comprise a highmoisture content, generally 30% to 60% moisture or greater with thebalance comprising solids. It is also contemplated that mixtures ofbinder material may be employed.

With respect to the feedstock and binder, where the binder contains ahigher moisture content, the use of an atomizer for dispensing moistureon to pans 28 and/or 30 may not be necessary. In a further variation,binder and feedstock material may be added to the pan(s) simultaneously.These process variations will be dependent upon the nature of thematerial to be pelletized or granulated.

Referring now to the photographs, FIG. 2 illustrates granulated sulfurpellets with an ammonium sulfate core created by the prior art techniqueas taught by Derdall et al. The pellets clearly include a sizeable coreoccupying a large amount of the volume of the particle. It is alsoevident that the cross section of the particles is nonuniform and insome cases hollow in localized areas. In addition, the particles are notspherical, but rather substantially aspherical. These factors alldepreciate the quality and industrial value of the particles.

FIG. 3 shows whole granulated sulfur pellets synthesized in accordancewith the Derdall et al. methodology. As is evident from the figure, theexterior of the granules is loose to provide a grainy surface texture.This lack of consolidation of the material results in the generation ofdust which, as indicated supra, creates significant handling problemsand in particular, increases the likelihood of a potential explosion.

In contrast to the above, FIGS. 4 and 5 demonstrate the high qualityparticles generated by the present methodology. Of particularsignificance is the fact that the particles/granules are completelydevoid of any core or seed, but rather are entirely uniform, continuousand solid throughout. FIG. 5 illustrates the granules in toto. It isreadily apparent that the granules have a different surface appearancethan those formulated by the prior art; this is further evinced by thelack of dust or grains surrounding the particles. The particles aresignificantly more consolidated, harder, tightly packed and include agreater amount of feedstock (at least 95% by weight) than the prior artgranules. Accordingly, the, advantages enumerated herein previously arerealized.

In respect of FIGS. 6 and 7, shown are potassium chloride granules madeby the technique set forth by Derdall et al. The Figures illustrate twodifferent forms of the compound and confirm the presence of the seedindicated as a critical factor to the generation of the particles.

With reference to FIGS. 8 and 10, shown are potassium chloride particlesformulated by practicing the methodology of one embodiment of theinvention. As illustrated, the particles are substantially spherical,devoid any core and lack the surface graininess of the particles of FIG.6. The particles illustrated include a sulfur compound.

FIG. 9 illustrates a sodium bicarbonate granule granulated by practicingthe technology set forth herein. Noteworthy is the spherical appearanceand consolidation of the particle.

The inventive technology established herein affords a commerciallyviable and industrially significant development in the granulation artaffording pellet content customization among other features.

Although embodiments of the invention have been described above, it isnot limited thereto and it will be apparent to those skilled in the artthat numerous modifications form part of the present invention insofaras they do not depart from the spirit, nature and scope of the claimedand described invention.

I claim:
 1. A wet granulation method for granulating a feedstock intogranules, comprising the steps of: providing a first feedstock havingabout 99.9% particle size of −150 mesh, of said 99.9% particle size of−150 mesh about 90% comprising a particle size of −200 mesh; providing abinder material having a moisture content; contacting said firstfeedstock with said binder; forming a pre-moistened mixture of saidbinder, said first feedstock and said moisture, said mixture having amoisture content of between 4% and 8% by weight; introducing saidpre-moistened mixture onto a pan granulator containing second feedstockdifferently sized from said first feedstock in a size distribution ofbetween −35 mesh and +150 mesh; maintaining moisture conditions on saidpan where the moisture content on said pan is between 1.5% and 11% byweight; and forming first granules on said pan directly from contact ofsaid pre-moistened mixture and said second feedstock in the absence ofseed material.
 2. The method as set forth in claim 1, wherein saidmoisture content is between about 1.5% and about 10.5%.
 3. The method asset forth in claim 2, wherein said first moisture content is about 8%.4. The method as set forth in claim 1, wherein said first granules arein the size range of −10 mesh to 100 mesh.
 5. The method as set forth inclaim 4, said method producing at least a 90% yield.
 6. The method asset forth in claim 1, wherein said feedstock is selected from the groupcomprising of sodium bicarbonate, potassium sulfate, potassium chloride,potassium nitrate, ammonium sulfate and sulfur.
 7. The method as setforth in claim 1, wherein said binder comprises about 60% moisture andabout 40% solids.
 8. The method as set forth in claim 7, wherein betweenabout 7% to about 9% by weight of said binder is added to said pan. 9.The method as set fourth in claim 1, further including the step ofadding an oil to formed first granules for dust control prior to furtherprocessing.
 10. The method as set forth in claim 9, wherein said oilcomprises an oil selected from the group consisting of canola oil,vegetable oil, mineral oil.
 11. The method as set forth in claim 1,wherein said binder is dry, said pre-moistened mixture deriving moisturecontent from the addition of water.
 12. The method as set forth in claim1, further including the step of treating said first granule in a secondpan to form second granules from said first granules wherein saidfeedstock for said second pan includes between about 20% to about 35%product in the size range of −10 mesh to about 100 mesh.
 13. The methodas set forth in claim 12, wherein said second granules from said secondpan comprise granules in a size range from between −4 mesh and −8 mesh.14. A wet granulation method for granulating a feedstock into granules,comprising the steps of: providing a first feedstock having about 99.9%particle size of −150 mesh of said 99.9% particle size of −150 meshabout 90% comprising a particle size of −200 mesh; providing a bindermaterial having a moisture content; contacting said first feedstock withsaid binder; forming a pre-moistened mixture of said binder, said firstfeedstock and said moisture, said mixture having a moisture content ofbetween 4% and 8% by weight; introducing said pre-moistened mixture ontoa pan granulator containing said first feedstock; maintaining panmoisture conditions where the moisture content on said pan is between15% to about 11% by weight; forming first granules on said pan directlyfrom contact of said pre-moistened mixture and said first feedstock inthe absence of seed material; passing formed first granules onto asecond pan granulator in the absence of said seed or nucleatingmaterial; and forming second granules in a different size distributionrelative to said first granules.